With the technology advancements in the fields of computer systems and electronic communications, semiconductor memory devices used for storing information have been gradually reduced in price and size but increased in capacity. Furthermore, as demand for energy efficiency also increases, semiconductor memory devices have been developed to suppress unnecessary current consumption.
Meanwhile, a variety of drivers should be provided to perform a read or write operation in DRAM. For example, DRAM requires a driver which drives a global input/output line to transmit data to the global input/output line during the read operation, and a driver which drives the global input/output line to transmit data inputted through a DQ pad to the global input/output line during the write operation.
In general, the drivers included in DRAM are implemented with MOS transistors. The MOS transistors are driven by a driving voltage VDDL that has a lower level than a power supply voltage VDD, in order to reduce current consumption during the read or write operation. Since such MOS transistors use the low-level driving voltage VDDL, MOS transistors that have a low threshold voltage are used.
However, since MOS transistors that have a low threshold voltage have a large amount of channel leakage current in a region where the read or write operation is excluded, a standby current increases. As a result, current consumption inevitably increases.